RP9P and cancer: establishment of 19 pseudogene pair signatures, which included 21 pseudogenes (ABCC6P2, ANXA2P2, AQP7P1, AZGP1P1, C3P1, CA5BP1, DSTNP2, HLA-J, HSPA7, LPAL2, NAPSB, NUDT16P1, PLGLA, RP9P)patients in high-risk group have an increased risk of worse prognosispseudogenes are primarily involved in cytokine receptor activity, T cell receptor signaling, chemokine signaling, NF-κB signaling, PD-L1 expression, and the PD-1 checkpoint pathway in cancer